/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.apache.flink.table.planner.calcite;

import org.apache.flink.table.planner.plan.FlinkCalciteCatalogReader;

import org.apache.calcite.config.CalciteConnectionConfigImpl;
import org.apache.calcite.jdbc.CalciteSchema;
import org.apache.calcite.plan.RelOptCluster;
import org.apache.calcite.prepare.CalciteCatalogReader;
import org.apache.calcite.rel.type.RelDataType;
import org.apache.calcite.rex.RexNode;
import org.apache.calcite.tools.FrameworkConfig;

import java.util.Collections;
import java.util.Properties;
import java.util.stream.Stream;

/**
 * Standard implementation of {@link SqlExprToRexConverter}.
 */
public class SqlExprToRexConverterImpl implements SqlExprToRexConverter {

	private final FlinkPlannerImpl planner;

	private final RelDataType tableRowType;

	public SqlExprToRexConverterImpl(
			FrameworkConfig config,
			FlinkTypeFactory typeFactory,
			RelOptCluster cluster,
			RelDataType tableRowType) {
		this.planner = new FlinkPlannerImpl(
			config,
			(isLenient) -> createEmptyCatalogReader(typeFactory),
			typeFactory,
			cluster
		);
		this.tableRowType = tableRowType;
	}

	@Override
	public RexNode convertToRexNode(String expr) {
		return convertToRexNodes(new String[]{expr})[0];
	}

	@Override
	public RexNode[] convertToRexNodes(String[] exprs) {
		final CalciteParser parser = planner.parser();
		return Stream.of(exprs)
			.map(parser::parseExpression)
			.map(node -> planner.rex(node, tableRowType))
			.toArray(RexNode[]::new);
	}

	// ------------------------------------------------------------------------------------------
	// Utilities
	// ------------------------------------------------------------------------------------------

	private static CalciteCatalogReader createEmptyCatalogReader(FlinkTypeFactory typeFactory) {
		return new FlinkCalciteCatalogReader(
			CalciteSchema.createRootSchema(false),
			Collections.emptyList(),
			typeFactory,
			new CalciteConnectionConfigImpl(new Properties()));
	}
}
